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GIFTS Blackbody Subsystem Critical Design Review Blackbody Requirements Flowdown. Fred Best 9 March 2004. Topics. GIFTS Calibration Scheme Flowdown of requirements Blackbody Error Contributions to GIFTS Calibration Overview of Top Level BB Subsystem Specifications. - PowerPoint PPT Presentation
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<GIFTS_BB_CDR_BB_Requirem_Flow.ppt>9 March 2004
GIFTSBlackbody SubsystemCritical Design Review
Blackbody Requirements Flowdown
Fred Best
9 March 2004
<GIFTS_BB_CDR_BB_Requirem_Flow.ppt>9 March 2004
Slide 2
Topics
• GIFTS Calibration Scheme
• Flowdown of requirements
• Blackbody Error Contributions to GIFTS Calibration
• Overview of Top Level BB Subsystem Specifications
<GIFTS_BB_CDR_BB_Requirem_Flow.ppt>9 March 2004
Slide 3
GIFTS Radiometric Calibration Concept
• Two small reference Blackbodies located behind telescope, combined with Space View.
• Blackbody design is scaled from the UW ground-based AERI and NAST / S-HIS aircraft instruments.
• Constraints on original S/C prevented traditional external large aperture blackbody configuration.
• Advantages compared to large external blackbody: (1) higher emissivity is practical with small size (2) protection from solar forcing.
<GIFTS_BB_CDR_BB_Requirem_Flow.ppt>9 March 2004
Slide 4
GIFTS Electro-optical Diagram
<GIFTS_BB_CDR_BB_Requirem_Flow.ppt>9 March 2004
Slide 5
GIFTS Sensor Module
BENCH
FORE OPTICS BAFFLEA-FOCAL BAFFLE
AFT OPTICS BAFFLE
FORE OPTICS SECONDARY BAFFLE
PMA BAFFLE
BLACKBODIESBlackbodiesAperture stop image at
blackbody aperture
<GIFTS_BB_CDR_BB_Requirem_Flow.ppt>9 March 2004
Slide 6
GIFTS Blackbody Absolute Calibration Budget
<GIFTS_BB_CDR_BB_Requirem_Flow.ppt>9 March 2004
Slide 7
GIFTS Blackbody Reproducibility Calibration Budget
<GIFTS_BB_CDR_BB_Requirem_Flow.ppt>9 March 2004
Slide 8
GIFTS Blackbody Error Sources-LW
0.0010.1 K 5 K
Longwave Band (800 cm-1)Tc=255, Th=290, Ts=240, Tt=280, Tm=250
-0.30
-0.20
-0.10
0.00
0.10
0.20
0.30
0.40
0.50
190 210 230 250 270 290 310
Scene Temperature [K]
BB Total Thot Tambient Ehot Eambient Tstructure Budget
0.1 K 0.001
Longwave Band (800 cm-1) AbsoluteTA=255, TH=290, Ts=240, Tt=280, Tm=250
<GIFTS_BB_CDR_BB_Requirem_Flow.ppt>9 March 2004
Slide 9
GIFTS Blackbody Error Sources-LW
0.00.014 K 5 K0.014 K 0.0
Longwave Band (800 cm-1) ReproducibilityTA=255, TH=290, Ts=240, Tt=280, Tm=250
Longwave Band (800 cm-1)Tc=255, Th=290, Ts=240, Tt=280, Tm=250
-0.04
-0.02
0.00
0.02
0.04
0.06
0.08
0.10
190 210 230 250 270 290 310
Scene Temperature [K]
BB Total Thot Tambient Ehot Eambient Tstructure Budget
<GIFTS_BB_CDR_BB_Requirem_Flow.ppt>9 March 2004
Slide 10
GIFTS Blackbody Error Sources-SW
0.0010.1 K 5 K0.1 K 0.001
Shortwave Band (1800 cm-1)Tc=255, Th=290, Ts=240, Tt=280, Tm=250
-0.10
0.00
0.10
0.20
0.30
0.40
0.50
190 210 230 250 270 290 310
Scene Temperature [K]
BB Total Thot Tambient Ehot Eambient Tstructure Budget
Shortwave Band (1800 cm-1) AbsoluteTA=255, TH=290, Ts=240, Tt=280, Tm=250
<GIFTS_BB_CDR_BB_Requirem_Flow.ppt>9 March 2004
Slide 11
GIFTS Blackbody Error Sources-SW
0.00.014 K 5 K0.014 K 0.0
Shortwave Band (1800 cm-1) ReproducibilityTc=255, Th=290, Ts=240, Tt=280, Tm=250
-0.02
0.00
0.02
0.04
0.06
0.08
0.10
190 210 230 250 270 290 310
Scene Temperature [K]
BB Total Thot Tambient Ehot Eambient Tstructure Budget
Shortwave Band (1800 cm-1) ReproducibilityTA=255, TH=290, Ts=240, Tt=280, Tm=250
<GIFTS_BB_CDR_BB_Requirem_Flow.ppt>9 March 2004
Slide 12
Summary of Top Level BB Requirements
Ambient Blackbody Nominal Set Point 255 K 255 K
Hot Blackbody Nominal Set Point 290 K 290 K
Temperature Measurement Uncertainty < 0.1 K (3 sigma) < 0.074 K (3 sigma)
Ambient Blackbody Emissivity > 0.996 > 0.998
Hot Blackbody Emissivity > 0.996 > 0.998
Emissivity Uncertainty < 0.002 < 0.00072 (3 sigma)
Wavelength 680 - 2,300 cm-1 680 - 2,300 cm-1
*Derived From GIRD Using Radiometric Model
Specification*Current Best
Estimate
<GIFTS_BB_CDR_BB_Requirem_Flow.ppt>9 March 2004
Slide 13
Summary of Top Level BB Requirements
Source Aperture 2.54 cm 2.54 cm
Source FOV (full angle) > 10° > 10°
Mass (two blackbodies plus controller board) < 2.4 kg < 2.1 kg
Power: average/max < 2.2/5.2 W < 2.2/5.2 W
Envelope < 8 x 8 x 15.5 cm < 8 x 8 x 15.4 cm
*Imposed by GIFTS Sensor Module Design
Specification*Current Best
Estimate